Over the last decade, numerous methods for motion tracking in brain imaging have been developed, but head motion during scanning pertains to be a significant problem causing artefacts and significantly reducing image quality.
Known methods include external tracking systems as well as image based motion tracking and correction. Many external tracking systems use markers attached to the subjects head. This potentially introduces errors and complicates the process of preparing the subject for the scan and therefore reduces the usability in clinical practice. Correspondingly, the image based motion tracking methods developed for medical brain imaging generally suffer from an inability to obtain sufficiently high temporal and spatial resolution at the same time. Further, the high resolution of modern medical scanners (down to tenths of a millimeter for MRI and a few millimeters for PET) set strict requirements to motion tracking systems.